package dao.impl;

import dao.UserDao;
import pojo.User;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class UserDaoImpl implements UserDao {
    @Override
    public List<User> findAll() {
        //jdbc 操作
        List<User> users = new ArrayList<>();
        Connection connection = null;
        PreparedStatement preparedStatement = null;

        //1、加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");

            //2.获取连接()
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection = DriverManager.getConnection(url, "root", "070517");

            //3.写sql
            String sql = "select * from user";

            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);

            //5.有参数设置参数

            //6.执行sql
            ResultSet resultSet = preparedStatement.executeQuery();

            //7.遍历结果集
            while (resultSet.next()) {
                User user = new User();
                user.setId(resultSet.getInt(1));
                user.setName(resultSet.getString(2));
                user.setPassword(resultSet.getString(3));
                //把对象添加到集合中
                users.add(user);

            }
            //返回集合
            return users;

        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //8.关闭资源
        }
    }
}
